2014 hsc chemistry - board of studies … · · 2015-06-10show all relevant working in questions...
TRANSCRIPT
2060
2014 HIGHER SCHOOL CERTIFICATEEXAMINATION
e
Chemistry
General Instructions
• Reading time – 5 minutes
• Working time – 3 hours
• Write using black or blue penBlack pen is preferred
• Draw diagrams using pencil
• Board-approved calculators maybe used
• A data sheet and a Periodic Tablare provided at the back of thispaper
• Write your Centre Number andStudent Number at the top ofpages 13, 17, 19, 21 and 23
Total marks – 100
Section I Pages 2–24
75 marks
This section has two parts, Part A and Part B
Part A – 20 marks
• Attempt Questions 1–20
• Allow about 35 minutes for this part
Part B – 55 marks
• Attempt Questions 21–31
• Allow about 1 hour and 40 minutes for this part
Section II Pages 25–37
25 marks
• Attempt ONE question from Questions 32–36
• Allow about 45 minutes for this section
Section I75 marks
Part A – 20 marksAttempt Questions 1–20Allow about 35 minutes for this part
Use the multiple-choice answer sheet for Questions 1–20.
1 In which layer of the atmosphere is ozone considered a pollutant?
(A) Mesosphere
(B) Stratosphere
(C) Thermosphere
(D) Troposphere
2 What is the IUPAC name of the following compound?
H
H
H
C C
F
Br
Br
H
C H
– 2 –
(A) 1,2-dibromo-2-fluoropropane
(B) 2,3-dibromo-2-fluoropropane
(C) 2-fluoro-2,3-dibromopropane
(D) 2-fluoro-1,2-dibromopropane
3 Which row of the table correctly matches the scientist(s) with their theory of acids?
4 Which of the following equations correctly represents catalytic cracking of a petroleumfraction?
(A) C15H32(g) C15H32(s)
(B) nC2H4(g) ⎯ (CH2 ⎯ CH2 )n ⎯ (s)
(C) C15H32(g) C7H16(g) + 4C2H4(g)
(D) C7H16(g) + 4C2H4(g) C15H32(g)
AlSi2O6⎯⎯⎯⎯⎯→
AlSi2O6⎯⎯⎯⎯⎯→
AlSi2O6⎯⎯⎯⎯⎯→
AlSi2O6⎯⎯⎯⎯⎯→
(A)
(B)
(C)
(D)
Scientist(s) Theory
Arrhenius Acids contain oxygen
Brönsted and Lowry Acids are proton donors
DavyAcids are able to producehydrogen ions in water
Lavoisier Acids contain hydrogen
– 3 –
5 Which row of the table correctly matches the reactant and the product of an additioneaction?r
6 Drinking water is regularly tested to ensure that it is safe for consumption.
Which of the following test results indicates the highest drinking-water quality?
CH3 CH2 CH2 CH2 OH CH3 CH2 CH CH2
CH3 CH2 CH CH3CH
Reactant Product
(B)
(A)
(C)
CH3 CH2 CH2 CH CH3
OH
CH3 CH CH CH2 CH3
(D)
CH3 CH2 CH2 CH3CH
Cl
O
OH
CH3 C
O
O
CH3 C
CH3
Dissolvedoxygen(mg/L)
Nitrate
(mg/L)
Total dissolved solids
(mg/L)
Turbidity
(NTU)
2 0.1 50 50
8 0.1 50 2
2 2 200 2
8 2 200 50
(A)
(B)
(C)
(D)
– 4 –
7 This table contains information on three indicators.
Indicator pH range Colour(lower pH – higher pH)
Methyl orange 3.1– 4.4 red – yellow
Methyl red 4.4 – 6.2 pink – yellow
Phenolphthalein 8.3–10.0 colourless – pink
A substance is tested with each of the indicators and the results are recorded below.
Indicator Colour
Methyl orange yellow
Methyl red yellow
Phenolphthalein colourless
– 5 –
Which of the following substances will produce these results?
(A) Lemonade pH 2.9
(B) White wine pH 4.2
(C) Tap water pH 7.2
(D) Ammonia pH 11.2
– 6 –
8 The graph shows the pH of a solution of a weak acid, HA, as a function of temperature.
0 50 100 150 2005.0
5.5
6.0
6.5
7.0
7.5
8.0
Temperature (°C)
pH
What happens as the temperature decreases?
(A) HA becomes less ionised and the H concentration increases.
(B) HA becomes less ionised and the H+ concentration decreases.
(C) HA becomes more ionised and the H+ concentration increases.
(D) HA becomes more ionised and the H+ concentration decreases.
+
9 Four compounds, W, X, Y and Z, are represented below.
Cl
Cl
H
C C
H
H
F
H
C
H
H
C H
C
H
H
C C
H
HHH
F
Cl
H
C Cl
H
Cl
H
C C
H
H
C
F
C F
H
HH
Compound W Compound X
Compound Y Compound Z
H
H
F
C C
H
H
Cl
H
C Cl
Which of the following is a pair of isomers?
(A) W and X
(B) W and Y
(C) X and Y
(D) Y and Z
10 The following equation represents a chemical system in equilibrium:
OCl−(aq) + H2O(l) HOCl(aq) + OH−(aq)
Which of the following is an acid/base conjugate pair?
(A) H2O / HOCl
(B) HOCl / OH−
(C) HOCl / OCl−
(D) OCl− / H2O
– 7 –
11 Which of the following does NOT represent the formation of a coordinate covalent bond?
+(A) ClC
H
H
H ClC
H
H
H
+
(B) + OH
H
HH+O
H
H
(C)
+
+ H+ N
H
H
H HN
H
H H
(D) +O O O O OO
12 The diagram shows the pH values of some substances.
0 1 2
Lemonjuice Wine Milk
Seawater Soap Bleach
3 4 5 6 7 8 9 10 11 12 13
Stomachacid
Orangejuice
Rainwater
Distilledwater
Bakingsoda
solutionLaundrydetergent
Ovencleaner
14
Based on the information provided, which of the following statements about the relativeconcentration of hydrogen ions is correct?
(A) It is 2 times higher in bleach than in milk.
(B) It is 10 times lower in stomach acid than in soap.
(C) It is 1000 times lower in distilled water than in wine.
(D) It is 100 times higher in laundry detergent than in baking soda solution.
– 8 –
13 This equation shows an equilibrium established in the synthesis of ammonia from itscomponent gases:
N2(g) + 3H2(g) 2NH3(g)
If the volume of the reaction chamber is suddenly halved at time T, which of thefollowing best depicts changes in the concentration of ammonia over time?
Con
c aa
T T
TimeTime
entr
atio
n of
mm
onia
Con
cent
ratio
n of
amm
onia
Time
Con
cent
ratio
n of
mm
onia
Con
cent
ratio
n of
amm
onia
Time
T
(A) (B)
(C) (D)
T
– 9 –
14 What is the pH of a 0.018 mol L−1 solution of hydrochloric acid?
(A) 0.74
(B) 0.96
(C) 1.04
(D) 1.74
15 If exactly one gram of each of the following compounds is treated with excesshydrochloric acid, which would release the greatest volume of CO2(g) at 25°C and100 kPa?
(A) K2CO3
(B) KHCO3
(C) Na2CO3
(D) NaHCO3
16 In which of the following reactions is the metal species reduced?
(A) 2FeCl2(aq) + Cl2(g) → 2FeCl3(aq)
(B) CuS(s) + O2(g) → Cu(s) + SO2(g)
(C) 2Al(OH)3(aq) → Al2O (s) + 3H l3 2O( )
(D) Ca(s) + 2HCl(aq) → CaCl2(aq) + H2(g)
17 What is the standard cell potential for the reaction of 1.0 mol L−1 acidified potassiumdichromate (K2Cr2O (aq)) with aqueous sulfur dioxide (SO aq7 2( )) under standardconditions?
(A) 1.20 V
(B) 1.52 V
(C) 2.24 V
(D) 3.20 V
– 10 –
18 This is a representation of a segment of the polymer nylon 6,6.
O
C
O
C
H
N(CH2)4H
N
O
C(CH2)6O
C
H
N(CH2)4H
N(CH2)6
Which of the following represents the two monomers that are used to produce nylon 6,6?
O
C(A) and(CH2)4 N
H
H(CH2)6 N
H
H
N
H
HHO
(B)
O
C and(CH2)4 C
OH
(CH2)4N
H
H
O
C
OH
O
HO
(CH2)4 N
H
H
N
H
H
O
C(C) and(CH2)6 C
OH
O
HO
(D) and (CH2)6 N
H
H
N
H
H
O
C (CH2)4 C
OH
O
HO
– 11 –
19 An experimental car using ethanol as a fuel source requires 2270 kJ of energy for everykilometre travelled.
Given that the heat of combustion of ethanol is 1360 kJ mol−1, what is the maximumdistance that the car can travel on 1.0 kilogram of ethanol?
(A) 1.7 km
(B) 13 km
(C) 28 km
(D) 36 km
20 This graph represents the yield of an equilibrium reaction at different temperature andpressure conditions inside a reaction vessel.
0
60
50
40
300 400 500
Temperature (°C)
600 700
30
20
10
Yie
ld o
f Z
(%
)
Pressure
30 atmospheres
100 atmospheres
200 atmospheres
Which of the following reactions could produce the trends shown in the graph?
(A) X(g) + Y(g) 3Z(g) ΔH = +100 kJ
(B) X(g) + Y(g) 2Z(g) ΔH = −100 kJ
(C) 2X(g) 2Y(g) Z(g) H 100 kJ+ Δ = +
(D) 4X(g) + 2Y(g) 3Z(g) ΔH = −100 kJ
– 12 –© 2014 Board of Studies, Teaching and Educational Standards NSW
2014 HIGHER SCHOOL CERTIFICATE EXAMINATION
Chemistry
Section I (continued)
Part B – 55 marksAttempt Questions 21–31Allow about 1 hour and 40 minutes for this part
Student Number
Answer the questions in the spaces provided. These spaces provide guidance for the expectedlength of response.
Show all relevant working in questions involving calculations.
Question 21 (3 marks)
The transuranic artificial element curium–242 can be produced in two ways.The nuclear equations for the two processes are given below.
3
Process A
Process B
95241
01
95242
96242
10Am Am Cm+ → → + −n e
94239
24
96242
01Pu He Cm+ → + n
Compare these two processes of production for the element curium–242.
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– 13 –2061
Centre Number
Question 22 (6 marks)
A student performed a first-hand investigation to determine the quantitative relationshipbetween heat of combustion and molar mass of alkanols. The student did this by burningdifferent alkanols to heat water as shown in the diagram below. The calculated heats ofcombustion for four of the alkanols are given in the table.
Question 22 continues on page 15
Spirit burner containing alkanol
Wire gauze
Tripod
Beaker containing water
Thermometer
Alkanol Molar mass(g mol-1)
Calculated heatof combustion(kJ mol-1)
Theoretical heat ofcombustion(kJ mol-1)
methanol 32 150 726
ethanol 46 950 1367
propan-1-ol 60 1500 2021
butan-1-ol 74 2250 2676
– 14 –
Question 22 (continued)
(a) On the grid below, graph both the calculated and the theoretical heat ofcombustion against the molar mass of the alkanols.
(b) Discuss the validity of the student’s investigation.
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End of Question 22
3
Heat of combustion versus molar mass
Molar mass(g mol–1)
Heat ofcombustion(kJ mol–1)
3
– 15 –
Question 23 (3 marks)
This diagram shows a town situated near agriculture and industry.
The town relies on the river for its water supply.
(a) Identify ONE chemical species that could be a contaminant of the water supply.
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(b) Explain the need to monitor the levels of a contaminant in water supplies.
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Agriculturalland
Agriculturalland
Car batteryfactory
Town
Town water supply
Creek
Riv
erR
iver
1
2
– 16 –© 2014 Board of Studies, Teaching and Educational Standards NSW
2014 HIGHER SCHOOL CERTIFICATE EXAMINATION
Chemistry
Section I – Part B (continued)
Question 24 (5 marks)
A solution contains carbonate, chloride and sulfate ions.
Describe a sequence of tests that could be used to confirm the presence of each ofthese ions. Include ONE relevant chemical equation.
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– 17 –2062
Centre Number
Student Number
Question 25 (4 marks)
Under conditions of low oxygen levels, octane can undergo incomplete combustionaccording to the following chemical equation:
2C8H18(l) + 17O2(g) → 6C(s) + 4CO(g) + 6CO2(g) + 18H2O(l)
(a) Explain the need to monitor this process. 2
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(b) Calculate the mass of soot (C(s)) produced if 4.2 moles of octane are combustedin this way.
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2
– 18 –© 2014 Board of Studies, Teaching and Educational Standards NSW
2014 HIGHER SCHOOL CERTIFICATE EXAMINATION
Chemistry
Section I – Part B (continued)
Question 26 (6 marks)
A first-hand investigation to produce an ester is to be carried out in a schoollaboratory, using an alkanol, an alkanoic acid and a suitable catalyst.
(a) Name an ester that could be produced in a school laboratory. 1
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(b) Describe how potential hazards associated with the three chemicals required forthis investigation could be addressed.
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– 19 –2063
Centre Number
Student Number
Question 27 (6 marks)
Limestone (CaCO3) contributes to the hardness of water by releasing Ca2+ ions inwater. The chemical equation for this exothermic reaction is shown.
CaCO3(s) + H2O(l) + CO2(g) Ca2+(aq) + 2HCO3−(aq)
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– 20 –© 2014 Board of Studies, Teaching and Educational Standards NSW
(a) Explain why increasing the temperature of hard water would reduce its hardness. 2
(b Describe how atomic absorption spectroscopy (AAS) could be used to measurethe effectiveness of heating water to reduce its hardness.
4
2014 HIGHER SCHOOL CERTIFICATE EXAMINATION
Chemistry
Section I – Part B (continued)
Question 28 (5 marks)
A galvanic cell has been constructed as shown in the diagram.
KNO3(aq) salt bridge
1.0 mol L–1 Cu(NO3)2(aq)1.0 mol L–1 nitrate saltsolution of X
Colourlesssolution
X metal(anode)
Cu metal(cathode)
Bluesolution
V
(a) Explain the colour change in the copper half-cell as the reaction proceeds. 2
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(b) The theoretical standard potential for this galvanic cell is 2.02 V.
dentify metal X and justify your answer.I
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– 21 –2064
Centre Number
Student Number
Question 29 (5 marks)
An experiment was performed to model the formation of acid rain. 5
A sample of sulfur was burned on a metal spoon. While alight, it was placed in a gasjar with some dry litmus paper.
Gas jar
Metal spoon
Lid
Burning sulfur
Dry litmus paper
When a fine mist of water was sprayed into the jar, the litmus paper turned red.
Assess the suitability of this experiment as a model for the formation of acid rain.
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– 22 –© 2014 Board of Studies, Teaching and Educational Standards NSW
2014 HIGHER SCHOOL CERTIFICATE EXAMINATION
ChemistrySection I – Part B (continued)
Question 30 (5 marks)
A batch of dry ice (solid CO2its purity, the following steps were carried out.
ted during manufacture. To determine) was contamina
Step 1: A 0.616 gram sample of the contaminated dry ice wasplaced in a clean, dry flask.
Step 2: 50.00 mL of 1.00 mol L−1 sodium hydroxide was added tothe flask. The sodium hydroxide was in excess.
Step 3: The flask was sealed to prevent loss of carbon dioxide gasand the reaction allowed to reach completion, according tothis equation:
2NaOH(aq) + CO (s) → Na aq l2 2CO3( ) + H2O( )
Step 4: The remaining sodium hydroxide was titrated against a1.00 mol L−1 solution of hydrochloric acid. The averagevolume of HCl used was 27.60 mL.
(a) Calculate the number of moles of NaOH added in Step 2. 1
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(b) Calculate the percentage purity by mass of this batch of dry ice. 4
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– 23 –2065
Centre Number
Student Number
Question 31 (7 marks)
With reference to the underlying chemistry and with relevant equations, assess theimpacts on society of TWO uses of ethanol.
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– 24 –© 2014 Board of Studies, Teaching and Educational Standards NSW
2014 HIGHER SCHOOL CERTIFICATE EXAMINATION
Chemistry
Section II
25 marksAttempt ONE question from Questions 32–36Allow about 45 minutes for this section
Answer parts (a)–(c) of the question in Section II Answer Booklet 1.Answer parts (d)–(e) of the question in Section II Answer Booklet 2.Extra writing booklets are available.
Show all relevant working in questions involving calculations.
Pages
Question 32 Industrial Chemistry ............................................................. 26–27
Question 33 Shipwrecks, Corrosion and Conservation ............................ 28–29
Question 34 The Biochemistry of Movement .......................................... 30–32
Question 35 The Chemistry of Art ........................................................... 33–34
Question 36 Forensic Chemistry .............................................................. 35–37
– 25 –2066
Question 32 — Industrial Chemistry (25 marks)
Answer parts (a)–(c) in Section II Answer Booklet 1.
(a) This diagram illustrates some of the properties of sulfuric acid. 3
Drop of concentrated H2SO4
Drop of dilute H2SO4
Drop of concentrated
or dilute H2SO4
Glass surfaceSteel surface
Vigorousbubbling
No bubbling No bubbling
Steel surface
Explain, with reference to the diagram, how sulfuric acid should be transported.
(b) Nitrosyl chloride is introduced into an empty container. It then dissociates intonitric oxide and chlorine according to the equation:
2NOCl(g) 2NO(g) + Cl2(g)
The reaction is endothermic.
(i) Explain the effect on the yield of NO(g) if the temperature is increased. 2
(ii) The equilibrium constant, K, for the reaction is 0.028. 3
Calculate the equilibrium concentration of NOCl(g) if the equilibriumoncentration of Cl2(g) is 0.17 mol L−1.c
Question 32 continues on page 27
– 26 –
Question 32 (continued)
(c) Electrolysis is used in the industrial production of sodium hydroxide.
(i) Contrast the energy transformations in galvanic and electrolytic cells. 2
(ii) The table shows the products of three different electrolytic cellsnvolving aqueous or molten sodium chloride.i
3
Cell Anode Cathode
X O2(g) H2(g)
Y Cl2(g) H2(g)
Z Cl2(g) Na(l)
Explain which of the three electrolytic cells from the table is used for theindustrial production of sodium hydroxide.
Answer parts (d)–(e) in Section II Answer Booklet 2.
(d) An investigation is to be conducted to model a chemical step involved in theolvay process.S
(i) Outline a valid procedure that could be used to carry out the investigation. 2
(ii) Describe TWO limitations associated with the procedure outlined inpart (i).
3
(e) Explain how the differences in the structure and composition of soaps andetergents determine their uses and their impacts on the environment.d
End of Question 32
7
– 27 –
Question 33 — Shipwrecks, Corrosion and Conservation (25 marks)
Answer parts (a)–(c) in Section II Answer Booklet 1.
(a) This diagram shows the various layers of a pipe. 3
Interior zinc coating
Powder coating
Polymer coating
99.99% pure zinc
Steel
Outline TWO reasons why this pipe would be resistant to corrosion.
(b) Iron corrodes differently under acidic and neutral conditions.
(i) Write an equation to represent the process of rusting under neutralconditions.
2
(ii) Explain why iron will corrode faster under acidic conditions than underneutral conditions.
3
– 28 –
Question 33 continues on page 29
Question 33 (continued)
(c) A wooden artefact was recovered from a shipwreck. After it was removed fromthe ocean, it was placed in a tank of distilled water. The water was changedweekly and the chloride ion concentration was monitored. After 10 weeks, theartefact was dried slowly in a controlled environment.
The graph shows the chloride ion concentration in the tank in the firstfive weeks.
10 2 3
Time (weeks)
[Cl–]
4 5
(i) Account for the shape of this graph. 2
(ii) Explain the possible effect on the artefact if it had been simply left to dryinstead of undergoing the procedure described above.
3
Answer parts (d)–(e) in Section II Answer Booklet 2.
(d) An investigation is to be set up in a school laboratory to determine the rate ofcorrosion of iron in different oxygen concentrations.
(i) Identify the variables that need to be kept constant in this investigation. 2
(ii) Describe TWO limitations in making qualitative and/or quantitativeobservations in this investigation.
3
(e) Explain why a range of factors should be considered when using electrolysis toclean and stabilise a metal artefact.
7
– 29 –
End of Question 33
Question 34 — The Biochemistry of Movement (25 marks)
Answer parts (a)–(c) in Section II Answer Booklet 1.
(a) The diagram represents the junction between a nerve and a muscle cell. Anaction potential in the nerve causes contraction in the muscle cell.
3
Nerve
Musclecell
Myofibrils
Contraction
Action potential
Vesicles ofacetylcholine (ACh)
Sarcolemma
Motor neuron
Action potential
Synaptic cleft
In your answer booklet, write steps 5 and 6 to show how this contraction occurs.
Step 1 Action potential travels down nerve to endplate
Step 2 ACh (chemical neurotransmitter) is released into synaptic cleft
Step 3 ACh initiates action potential on the muscle cell membrane (sarcolemma)
Step 4 Action potential travels along sarcolemma, through T tubules to sarcoplasmic reticulum
Step 5
Step 6
Step 7 Enzyme (myosin ATP-ase) allows breakdown of ATP to release energy
Step 8 Actin and myosin slide over each other
tep 9 Muscle shortens (contracts)S
– 30 –
Question 34 continues on page 31
Question 34 (continued)
(b) (i) Name an enzyme and outline its function. 2
(ii) xplain how a change in pH might change the shape and structure of annzyme.e
3E
(c) Glucose is a carbohydrate monomer which forms the extensively branchedpolymer, glycogen.
(i) Explain an advantage of the extensive branching of the chains of alycogen molecule.g
2
(ii) The graph shows the distribution of molecular mass of a large numberof glycogen molecules.
3
2.00 4.0 6.0 8.0
Average molecular mass
Molecular mass (× 105 g mol–1)
Number ofglycogenmolecules
Calculate the number of glucose monomers in an average glycogenmolecule.
Question 34 continues on page 32
– 31 –
Question 34 (continued)
Answer parts (d)–(e) in Section II Answer Booklet 2.
(d) An investigation is to be set up to represent the structure of fatty acids.
(i) Identify the essential features of fatty acid molecules that should beincluded in this representation.
2
(ii) Describe TWO limitations of using models or diagrams to represent fattyacid molecules.
3
(e) Explain how damage to mitochondria affects ATP production and energy outputof cells.
End of Question 34
7
– 32 –
Question 35 — The Chemistry of Art (25 marks)
Answer parts (a)–(c) in Section II Answer Booklet 1.
(a) The successive ionisation energies of aluminium are presented below. 3
100
5 000
10 000
15 000
20 000
2 3
Ionisation number
Ioni
satio
n en
ergy
(kJ
mol
–1)
4 5 6 7
Explain the trend in ionisation energy.
(b) Pigments play a significant role in the creation of cave paintings by Aboriginalpeople.
(i) Outline the process used to prepare and attach pigments to cave walls. 2
(ii) Describe THREE pigments used by Aboriginal people in traditional art,ith reference to their chemical composition and colour.w
3
– 33 –
Question 35 continues on page 34
Question 35 (continued)
(c) Three electron configurations are presented in the table. For elemental titanium,the ground state is represented by I, while II and III are both invalid ground stateelectron configurations.
I
II
III
1s 2s 2p 3s 3p 4s 3d
Electron Configurations
Groundstate
Invalid
Invalid
(i) Write a valid electron configuration for Ti . 23+
(ii) Explain why II and III do not represent the ground state configuration forelemental titanium.
3
Answer parts (d)–(e) in Section II Answer Booklet 2.
(d) An investigation is to be conducted to study the changes in oxidation state of atransition metal.
(i) Outline a valid procedure that could be used to carry out the investigation. 2
(ii) Describe TWO limitations of the procedure outlined in part (i). 3
(e) Explain the role of electrons in determining colour.
End of Question 35
7
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Question 36 — Forensic Chemistry (25 marks)
Answer parts (a)–(c) in Section II Answer Booklet 1.
(a) This picture shows a forensic scientist collecting a blood sample from a crimescene.
3
Explain TWO errors that this scientist is making while collecting the blood sample.
(b) Hydrolysis can be used to break down proteins into amino acids.
(i) This equation represents the hydrolysis of a dipeptide. 2
+H2N CH
CH3
CH2N
H
C
O O
CH2 COH
+ H2O
In your answer booklet, draw the TWO products of the hydrolysis ofthe dipeptide.
(ii) Describe how protein hydrolysis is used in forensic analysis. 3
Question 36 continues on page 36
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Question 36 (continued)
(c) (i) An unknown substance was collected. It was analysed and its masspectrum collected.s
2
100
90
80
70
60
50
40
30
20
10
0
0 50 100 150 200 250 300
Mass to charge ratio
Mass spectrum of unknown substance
Rel
ativ
e in
tens
ity
This table shows the mass to charge ratio of a selection of fragments inthe mass spectrum for three compounds of interest in forensicinvestigations.
Compound name Significant fragments (mass to charge ratio)
Caffeine 67 109 194
Cocaine 82 94 182
Paracetamol 43 109 151
Using the information in the table, identify the unknown substance andjustify your choice.
(ii) Describe how mass spectrometry can be useful for analysing forensicvidence.e
3
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Question 36 continues on page 37
Question 36 (continued)
Answer parts (d)–(e) in Section II Answer Booklet 2.
(d) An investigation is to be conducted in a school laboratory to separate organicompounds using chromatography.c
(i) Outline a valid procedure that could be used in a school laboratory tocarry out the investigation.
2
(ii) Describe TWO limitations of carrying out the procedure outlined inpart (i).
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3
(e) Explain why DNA evidence may be challenged when used in court cases. 7
End of paper
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© 2014 Board of Studies, Teaching and Educational Standards NSW
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2014 HIGHER SCHOOL CERTIFICATE EXAMINATION
Chemistry
DATA SHEET
2067
Avogadro constant, NA .................................................................. 6.022 × 1023 mol–1
Volume of 1 mole ideal gas: at 100 kPa andat 0°C (273.15 K) ...................... 22.71 Lat 25°C (298.15 K) .................... 24.79 L
Ionisation constant for water at 25°C (298.15 K), Kw ................. 1.0 × 10–14
Specific heat capacity of water ..................................................... 4.18 × 103 J kg–1 K–1
Some useful formulaepH = –log10[H+ ] ΔH = –m CΔT
Some standard potentials
K+ + e– K(s) –2.94 V
Ba2+ + 2e– Ba(s) –2.91 V
Ca2+ + 2e– Ca(s) –2.87 V
Na+ + e– Na(s) –2.71 V
Mg2+ + 2e– Mg(s) –2.36 V
Al3+ + 3e– Al(s) –1.68 V
Mn2+ + 2e– Mn(s) –1.18 V
H2O + e– –1 H (g) + OH–2 2 –0.83 V
Zn2+ + 2e– Zn(s) –0.76 V
Fe2+ + 2e– Fe(s) –0.44 V
Ni2+ + 2e– Ni(s) –0.24 V
Sn2+ + 2e– Sn(s) –0.14 V
Pb2+ + 2e– Pb(s) –0.13 V
H+ + e– –1 H2 2(g) 0.00 V
SO 2– + 4H+ + 2e– SO (aq4 ) 2 + 2H O 0.16 V2
Cu2+ + 2e– Cu(s) 0.34 V
–1 O2(g) + H2 2O + 2e– 2OH– 0.40 V
Cu+ + e– Cu(s) 0.52 V
–1 I2(s) 2 + e– I– 0.54 V
–1 I2(aq) 2 + e– I– 0.62 V
Fe3+ + e– Fe2+ 0.77 V
Ag+ + e– Ag(s) 0.80 V
–1 Br (l) + e–2 2 Br– 1.08 V
–1 Br2 2(aq) + e– Br– 1.10 V
–1 O ( +g) –2 2 + 2H + 2e H2O 1.23 V
–1 Cl (g) + e– Cl–2 2 1.36 V
–1 Cr2O 2–7 + 7H+
2 + 3e– Cr3+ + –7 H2 2O 1.36 V
–1 Cl2(aq) + e– Cl– 1.40 V2
MnO –4 + 8H+ + 5e– Mn2+ + 4H2O 1.51 V
–1 F2(g) + e– F– 2.89 V2
Aylward and Findlay, SI Chemical Data (5th Edition) is the principal source of data forthis examination paper. Some data may have been modified for examination purposes.
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PERIODIC TABLE OF THE ELEMENTS
112Cn
Copernicium
9F
19.00Fluorine
17Cl
35.45Chlorine
35Br
79.90Bromine
53I
126.9Iodine
85At
Astatine
7N
14.01Nitrogen
15P
30.97Phosphorus
33As
74.92Arsenic
51Sb
121.8Antimony
83Bi
209.0Bismuth
5B
10.81Boron
13Al
26.98Aluminium
31Ga
69.72Gallium
49In
114.8Indium
81Tl
204.4Thallium
107Bh
Bohrium
108Hs
Hassium
109Mt
Meitnerium
110Ds
Darmstadtium
111Rg
Roentgenium
87Fr
Francium
88Ra
Radium
89–103
Actinoids
104Rf
Rutherfordium
105Db
Dubnium
106Sg
Seaborgium
57La
138.9Lanthanum
89Ac
Actinium
1H
1.008Hydrogen KEY
Atomic Number 79Symbol Au
tandard Atomic Weight 197.0Name Gold
2He
4.003Helium
3Li
6.941Lithium
4Be
9.012Beryllium
S
6C
12.01Carbon
8O
16.00Oxygen
10Ne
20.18Neon
11Na
22.99Sodium
12Mg
24.31Magnesium
14Si
28.09Silicon
16S
32.07Sulfur
18Ar
39.95Argon
19K
39.10Potassium
20Ca
40.08Calcium
21Sc
44.96Scandium
22Ti
47.87Titanium
23V
50.94Vanadium
24Cr
52.00Chromium
25Mn
54.94Manganese
26Fe
55.85Iron
27Co
58.93Cobalt
28Ni
58.69Nickel
29Cu
63.55Copper
30Zn
65.38Zinc
32Ge
72.64Germanium
34Se
78.96Selenium
36Kr
83.80Krypton
37Rb
85.47Rubidium
38Sr
87.61Strontium
39Y
88.91Yttrium
40Zr
91.22Zirconium
41Nb
92.91Niobium
42Mo
95.96Molybdenum
43Tc
Technetium
44Ru
101.1Ruthenium
45Rh
102.9Rhodium
46Pd
106.4Palladium
47Ag
107.9Silver
48Cd
112.4Cadmium
50Sn
118.7Tin
52Te
127.6Tellurium
54Xe
131.3Xenon
55Cs
132.9Caesium
56Ba
137.3Barium
57–71
Lanthanoids
72Hf
178.5Hafnium
73Ta
180.9Tantalum
74W
183.9Tungsten
75Re
186.2Rhenium
76Os
190.2Osmium
77Ir
192.2Iridium
78Pt
195.1Platinum
79Au
197.0Gold
80Hg
200.6Mercury
82Pb
207.2Lead
84Po
Polonium
86Rn
Radon
58Ce
140.1Cerium
59Pr
140.9Praseodymium
60Nd
144.2Neodymium
61Pm
Promethium
62Sm
150.4Samarium
63Eu
152.0Europium
64Gd
157.3Gadolinium
65Tb
158.9Terbium
66Dy
162.5Dysprosium
67Ho
164.9Holmium
68Er
167.3Erbium
69Tm
168.9Thulium
70Yb
173.1Ytterbium
71Lu
175.0Lutetium
90Th
232.0Thorium
91Pa
231.0Protactinium
92U
238.0Uranium
93Np
Neptunium
94Pu
Plutonium
95Am
Americium
96Cm
Curium
97Bk
Berkelium
98Cf
Californium
99Es
Einsteinium
100Fm
Fermium
101Md
Mendelevium
102No
Nobelium
103Lr
Lawrencium
Actinoids
Lanthanoids
Elements with atomic numbers 113 and above have been reported but not fully authenticated.Standard atomic weights are abridged to four significant figures.Elements with no reported values in the table have no stable nuclides.The International Union of Pure and Applied Chemistry Periodic Table of the Elements (February 2010 version) is the principal source of data. Some data may have been modified.